http://www.brookings.edu/iraqindex
Read the data for yourself then. Link above
All of that data is for US and British military and Iraqi Police and "Military" only. It says nothing of civilian deaths whatsoever. And the Iraqi Police deaths haven't declined significantly. Just because fewer American and British soldiers are being killed doesn't make it more peaceful; it merely means the violence is being targeted elsewhere. Look at the numbers of IEDs and bombs - they are still high.